The present invention relates to implantable medical electrical leads, and more particularly relates to multi-lumen, multi-conductor leads.
In the context of implantable electrical leads, such as those employed in conjunction with implantable pacemakers, implantable nerve stimulators, and implantable cardioverter/defibrillators, conductors typically have been either tinsel wire or coiled conductors. Recently, however, there has been an increasing level of interest in the use of new conductor types. One of the most promising new conductor types is the wire rope or cable (hereafter cable) conductor, comprising multiple strands, each strand comprising a number of very fine wires. In some cases, the conductors are provided with a thin coating of teflon or other insulating polymer. Examples of such conductors are described in U.S. Pat. No. 5,324,321 issued to Pohndorf et al., in U.S. Pat. No. 5,246,014, issued to Williams et al. and U.S. Pat. No. 4,964,414, issued to Handa et al., all incorporated herein by reference in their entireties.
In working cable type conductors, the inventors have determined that there are some difficulties associated with coupling the conductors to connectors, electrodes, sensors or other components. In particular, such conductors, in the sizes used for implantable electrical leads, are difficult to crimp, and the very fine wires employed tend to melt when welded. Moreover, if insulated, the cables typically must be stripped at their ends, prior to attachment.